A prior-art water trap for use in a breathing gas line of an anesthesia apparatus or respirator for separating moisture contained in the breathing gas appears, for example, from DE 199 01 590 Cl (corresponding to U.S. Pat. No. 6,117,214). The breathing gas, from which the moisture has been removed, flows downstream of the water trap especially into an infrared optical measuring unit for the analysis or determination of the concentration of constituents of the breathing gas or gaseous anesthetics contained in the breathing gas. Just like the water trap according to the present invention, the prior-art water trap can be replaceably connected to a holder of an anesthesia apparatus.
The water traps used so far as described in the area of medical engineering include both water traps for single-time use and water traps for multiple use, the water container for the moisture collected being emptied in the latter case, in general, by the operating staff after a certain operating time by means of a syringe and put out of operation after certain intervals of use. It may happen that the gas measurement will fail if the replacement intervals are not observed.